CN117704968A - Lithium battery winding OverHang detection method and system based on image projection - Google Patents

Lithium battery winding OverHang detection method and system based on image projection Download PDF

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Publication number
CN117704968A
CN117704968A CN202410167273.9A CN202410167273A CN117704968A CN 117704968 A CN117704968 A CN 117704968A CN 202410167273 A CN202410167273 A CN 202410167273A CN 117704968 A CN117704968 A CN 117704968A
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dimensional discrete
discrete array
value
lithium battery
calculating
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CN117704968B (en
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杨牧
郑晔
张董
赵海江
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Techmach Corp
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Techmach Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/0002—Inspection of images, e.g. flaw detection
    • G06T7/0004—Industrial image inspection
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/10—Segmentation; Edge detection
    • G06T7/13—Edge detection
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/70—Determining position or orientation of objects or cameras
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Theoretical Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Secondary Cells (AREA)

Abstract

The invention relates to the technical field of lithium batteries and discloses a lithium battery winding OverHang detection method and system based on image projection, wherein image shooting is carried out on a lithium battery to be detected, and an original image is determined; extracting an effective area of an original image, calculating an average gray value of each column of the image in the effective area, and constructing a one-dimensional discrete array; calculating the one-dimensional discrete array to obtain a one-dimensional discrete array, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array; calibrating a negative electrode identification position and a positive electrode identification position based on the edge position of the negative electrode plate and the edge position of the diaphragm; and calculating the OverHang value according to the negative electrode identification position and the positive electrode identification position, converting the two-dimensional image into a one-dimensional discrete array, and analyzing the one-dimensional discrete array, so that the detection data quantity and the detection time are reduced, the detection accuracy of the lithium battery OverHang is improved, and the service performance of the lithium battery is improved.

Description

Lithium battery winding OverHang detection method and system based on image projection
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a lithium battery winding OverHang detection method and system based on image projection.
Background
Lithium batteries are a type of battery using a nonaqueous electrolyte solution with lithium metal or a lithium alloy as a positive/negative electrode material. Lithium metal batteries were first proposed and studied in 1912. The chemical characteristics of lithium metal are very active, so that the processing, storage and use of lithium metal have very high requirements on environment. With the development of science and technology, lithium batteries have become the mainstream. Lithium batteries can be broadly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium ion batteries do not contain lithium in the metallic state and are rechargeable.
In the current design of the lithium battery with the winding structure, the negative electrode has an area allowance in the width and length directions compared with the positive electrode, and the OverHang refers to that the length of the negative electrode plate is more than the part outside the positive electrode plate in the width direction. In the measurement in the width direction, since a diaphragm is provided between the negative electrode sheet and the positive electrode sheet, the portion of the negative electrode sheet beyond the positive electrode sheet cannot be directly measured. The lithium battery has high detection precision and high speed requirement. In the related art, the x-ray image is generally adopted to calculate the OverHang of the battery, however, the method has certain limitation, is complex in calculation, low in precision and low in calculation universality, and does not meet the detection requirement of the lithium battery.
Therefore, how to provide a lithium battery winding OverHang detection method and system based on image projection is a technical problem to be solved at present.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a lithium battery winding OverHang detection method and system based on image projection.
In order to achieve the above purpose, the invention provides a lithium battery winding OverHang detection method based on image projection, which comprises the following steps:
shooting an image of the lithium battery to be detected, and determining an original image of the lithium battery to be detected;
extracting an effective area of the original image, wherein the effective area is an overlength detection area of the lithium battery to be detected;
calculating the average gray value of each column of the image in the effective area, and constructing a one-dimensional discrete array A1;
calculating the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
calibrating a negative electrode identification position and a positive electrode identification position based on the edge position of the negative electrode piece and the edge position of the diaphragm;
and calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
Further, when calculating the average gray value of each column of the image in the effective area and constructing the one-dimensional discrete array A1, the method includes:
the one-dimensional discrete array A1 is calculated according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
Further, when the one-dimensional discrete array A1 is calculated to obtain a one-dimensional discrete array A4, the method includes:
taking the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, taking the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and performing polynomial curve fitting based on a least square method to obtain a continuous function；
Calculating the continuous functionIs>And second derivative->；
From the second derivativeThe points of 0 are combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
comparing the one-dimensional discrete array A3 with a preset judgment threshold value, extracting points with absolute values larger than the judgment threshold value in the one-dimensional discrete array A3, and obtaining a one-dimensional discrete array A4, wherein the one-dimensional discrete array A4 is a suspected edge conforming to a set gradient value.
Further, when determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4, the method comprises the following steps:
taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative electrode plate;
the minimum value in the one-dimensional discrete array A4 is taken as the edge position of the diaphragm.
Further, when calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position, the method includes:
calculating a first distance d1 of the negative electrode pole piece relative to the negative electrode identification position;
calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
calculating the over Hang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
calculating the OverHang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
In order to achieve the above object, the present invention further provides a lithium battery winding OverHang detection system based on image projection, the system comprising:
the shooting module is used for shooting images of the lithium battery to be detected and determining an original image of the lithium battery to be detected;
the extraction module is used for extracting an effective area of the original image, wherein the effective area is an overHang detection area of the lithium battery to be detected;
the construction module is used for calculating the average gray value of each column of the image in the effective area and constructing a one-dimensional discrete array A1;
the determining module is used for carrying out calculation processing on the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
the calibration module is used for calibrating the negative electrode identification position and the positive electrode identification position based on the edge position of the negative electrode plate and the edge position of the diaphragm;
and the calculating module is used for calculating the over-Hang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
Further, the construction module is specifically configured to:
the construction module is used for calculating the one-dimensional discrete array A1 according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
Further, the determining module is specifically configured to:
the determining module is configured to use the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, use the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and perform polynomial curve fitting based on a least square method to obtain a continuous function；
The determining module is used for calculating the continuous functionIs>And second derivative->；
The determining module is used for determining the second derivativePoint of 0Is combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
the determining module is used for substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
the determining module is configured to compare the one-dimensional discrete array A3 with a preset judgment threshold, extract a point in the one-dimensional discrete array A3 where an absolute value is greater than the judgment threshold, and obtain a one-dimensional discrete array A4, where the one-dimensional discrete array A4 is a suspected edge that conforms to a set gradient value.
Further, the determining module is specifically configured to:
the determining module is used for taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative pole piece;
the determining module is used for taking the minimum value in the one-dimensional discrete array A4 as the edge position of the diaphragm.
Further, the computing module is specifically configured to:
the calculation module is used for calculating a first distance d1 of the negative pole piece relative to the negative pole identification position;
the calculation module is used for calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
the calculation module is used for calculating the OverHang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
the calculation module is used for calculating the over Hang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
The invention provides a lithium battery winding OverHang detection method and system based on image projection, which have the following beneficial effects compared with the prior art:
the invention discloses a lithium battery winding OverHang detection method and system based on image projection, wherein the method comprises the following steps: shooting an image of the lithium battery to be detected, and determining an original image of the lithium battery to be detected; extracting an effective area of an original image, calculating an average gray value of each column of the image in the effective area, and constructing a one-dimensional discrete array A1; calculating the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4; calibrating a negative electrode identification position and a positive electrode identification position based on the edge position of the negative electrode plate and the edge position of the diaphragm; according to the method, the two-dimensional image is converted into a one-dimensional discrete array, and then the one-dimensional discrete array is analyzed, so that the detection data quantity and the detection time are reduced, the detection accuracy of the lithium battery over-Hang is improved, and the service performance of the lithium battery is improved.
Drawings
Fig. 1 shows a schematic flow chart of a lithium battery winding OverHang detection method based on image projection in an embodiment of the invention;
fig. 2 shows a schematic structural diagram of a lithium battery winding OverHang detection system based on image projection in an embodiment of the invention.
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
In the description of the present application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
The following is a description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings.
As shown in fig. 1, an embodiment of the invention discloses a lithium battery winding OverHang detection method based on image projection, which comprises the following steps:
s110: shooting an image of the lithium battery to be detected, and determining an original image of the lithium battery to be detected;
in this embodiment, an industrial camera may be used to capture images of the lithium battery to be detected.
S120: extracting an effective area of the original image, wherein the effective area is an overlength detection area of the lithium battery to be detected;
s130: calculating the average gray value of each column of the image in the effective area, and constructing a one-dimensional discrete array A1;
in some embodiments of the present application, when calculating the average gray value of each column of the image in the effective area, constructing the one-dimensional discrete array A1 includes:
the one-dimensional discrete array A1 is calculated according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
In this embodiment, a part of the one-dimensional discrete array A1 is exemplified as follows:
the beneficial effects of the technical scheme are as follows: the one-dimensional discrete array A1 is obtained, so that a foundation can be laid for detecting the over-Hang value of the lithium battery to be detected, and the accuracy of the over-Hang value of the lithium battery to be detected is ensured.
S140: calculating the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
in some embodiments of the present application, when performing calculation processing on the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, the method includes:
taking the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, taking the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and performing polynomial curve fitting based on a least square method to obtain a continuous function；
Calculating the continuous functionIs>And second derivative->；
From the second derivativeThe points of 0 are combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
comparing the one-dimensional discrete array A3 with a preset judgment threshold value, extracting points with absolute values larger than the judgment threshold value in the one-dimensional discrete array A3, and obtaining a one-dimensional discrete array A4, wherein the one-dimensional discrete array A4 is a suspected edge conforming to a set gradient value.
In this embodiment, since the OverHang detection area of each lithium battery to be detected is different, the obtained one-dimensional discrete array is also different, and the corresponding continuous function is further obtainedThat is, different, thus calculating the continuous function +.>Can be used, not onlyThe following are given as examples.
In this embodiment, the one-dimensional discrete array A2 is a suspected edge in the effective area.
In this embodiment, a part of the one-dimensional discrete array A2 is exemplified as follows:
in this embodiment, a part of the one-dimensional discrete array A3 is exemplified as follows:
in this embodiment, the determination threshold may be set according to actual situations, and is not particularly limited herein.
In this embodiment, a part of the one-dimensional discrete array A4 is exemplified as follows:
the beneficial effects of the technical scheme are as follows: the invention can process the one-dimensional discrete array A1, thereby providing reliable data support for the determination of the edge position of the negative electrode plate and the edge position of the diaphragm.
In some embodiments of the present application, when determining the anode electrode tab edge position and the separator edge position from the one-dimensional discrete array A4, the method includes:
taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative electrode plate;
the minimum value in the one-dimensional discrete array A4 is taken as the edge position of the diaphragm.
S150: calibrating a negative electrode identification position and a positive electrode identification position based on the edge position of the negative electrode piece and the edge position of the diaphragm;
in this embodiment, since the edge position of the negative electrode plate and the edge position of the diaphragm are determined, the edge position of the positive electrode plate can be determined, the position of the left side (10 mm/camera resolution of the negative electrode) of the diaphragm in the effective area for negative electrode detection is calibrated as the negative electrode identification position, and the position of the left side (10 mm/camera resolution of the positive electrode) of the diaphragm in the effective area for positive electrode detection is calibrated as the positive electrode identification position.
S160: and calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
In some embodiments of the present application, when calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position, the method includes:
calculating a first distance d1 of the negative electrode pole piece relative to the negative electrode identification position;
calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
calculating the over Hang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
calculating the OverHang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
The beneficial effects of the technical scheme are as follows: the invention greatly reduces the detection data volume and the detection time, realizes the accurate detection of the over-Hang value of the lithium battery to be detected, and further can effectively improve the service performance of the lithium battery.
In order to further explain the technical idea of the invention, the technical scheme of the invention is described with specific application scenarios.
Correspondingly, as shown in fig. 2, the application further provides a lithium battery winding OverHang detection system based on image projection, and the system comprises:
the shooting module is used for shooting images of the lithium battery to be detected and determining an original image of the lithium battery to be detected;
the extraction module is used for extracting an effective area of the original image, wherein the effective area is an overHang detection area of the lithium battery to be detected;
the construction module is used for calculating the average gray value of each column of the image in the effective area and constructing a one-dimensional discrete array A1;
the determining module is used for carrying out calculation processing on the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
the calibration module is used for calibrating the negative electrode identification position and the positive electrode identification position based on the edge position of the negative electrode plate and the edge position of the diaphragm;
and the calculating module is used for calculating the over-Hang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
In some embodiments of the present application, the building block is specifically configured to:
the construction module is used for calculating the one-dimensional discrete array A1 according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
In some embodiments of the present application, the determining module is specifically configured to:
the determining module is configured to use the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, use the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and perform polynomial curve fitting based on a least square method to obtain a continuous function；
The determining module is used for calculating the continuous functionIs>And second derivative->；
The determining module is used for determining the second derivativeThe points of 0 are combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
the determining module is used for substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
the determining module is configured to compare the one-dimensional discrete array A3 with a preset judgment threshold, extract a point in the one-dimensional discrete array A3 where an absolute value is greater than the judgment threshold, and obtain a one-dimensional discrete array A4, where the one-dimensional discrete array A4 is a suspected edge that conforms to a set gradient value.
In some embodiments of the present application, the determining module is specifically configured to:
the determining module is used for taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative pole piece;
the determining module is used for taking the minimum value in the one-dimensional discrete array A4 as the edge position of the diaphragm.
In some embodiments of the present application, the computing module is specifically configured to:
the calculation module is used for calculating a first distance d1 of the negative pole piece relative to the negative pole identification position;
the calculation module is used for calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
the calculation module is used for calculating the OverHang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
the calculation module is used for calculating the over Hang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
Although the invention has been described hereinabove with reference to embodiments, various modifications thereof may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the features of the disclosed embodiments may be combined with each other in any manner as long as there is no structural conflict, and the entire description of these combinations is not made in the present specification merely for the sake of omitting the descriptions and saving resources. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Those of ordinary skill in the art will appreciate that: the above is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that the present invention is described in detail with reference to the foregoing embodiments, and modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The lithium battery winding OverHang detection method based on image projection is characterized by comprising the following steps of:
shooting an image of the lithium battery to be detected, and determining an original image of the lithium battery to be detected;
extracting an effective area of the original image, wherein the effective area is an overlength detection area of the lithium battery to be detected;
calculating the average gray value of each column of the image in the effective area, and constructing a one-dimensional discrete array A1;
calculating the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
calibrating a negative electrode identification position and a positive electrode identification position based on the edge position of the negative electrode piece and the edge position of the diaphragm;
and calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
2. The method for detecting the lithium battery winding OverHang based on image projection according to claim 1, wherein when calculating the average gray value of each column of the image in the effective area, constructing a one-dimensional discrete array A1 comprises:
the one-dimensional discrete array A1 is calculated according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
3. The method for detecting the lithium battery winding OverHang based on the image projection according to claim 1, wherein when the one-dimensional discrete array A1 is calculated, the method comprises the following steps:
taking the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, taking the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and performing polynomial curve fitting based on a least square method to obtain a continuous function；
Calculating the continuous functionIs>And second derivative->；
From the second derivativeThe points of 0 are combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
comparing the one-dimensional discrete array A3 with a preset judgment threshold value, extracting points with absolute values larger than the judgment threshold value in the one-dimensional discrete array A3, and obtaining a one-dimensional discrete array A4, wherein the one-dimensional discrete array A4 is a suspected edge conforming to a set gradient value.
4. The method for detecting the lithium battery winding OverHang based on image projection according to claim 1, wherein when determining the edge position of the negative electrode piece and the edge position of the diaphragm according to the one-dimensional discrete array A4, the method comprises the following steps:
taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative electrode plate;
the minimum value in the one-dimensional discrete array A4 is taken as the edge position of the diaphragm.
5. The method for detecting the lithium battery winding OverHang based on image projection according to claim 1, wherein when calculating the OverHang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position, the method comprises the following steps:
calculating a first distance d1 of the negative electrode pole piece relative to the negative electrode identification position;
calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
calculating the over Hang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
calculating the OverHang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
6. Lithium electricity coiling OverHang detecting system based on image projection, characterized in that, the system includes:
the shooting module is used for shooting images of the lithium battery to be detected and determining an original image of the lithium battery to be detected;
the extraction module is used for extracting an effective area of the original image, wherein the effective area is an overHang detection area of the lithium battery to be detected;
the construction module is used for calculating the average gray value of each column of the image in the effective area and constructing a one-dimensional discrete array A1;
the determining module is used for carrying out calculation processing on the one-dimensional discrete array A1 to obtain a one-dimensional discrete array A4, and determining the edge position of the negative electrode plate and the edge position of the diaphragm according to the one-dimensional discrete array A4;
the calibration module is used for calibrating the negative electrode identification position and the positive electrode identification position based on the edge position of the negative electrode plate and the edge position of the diaphragm;
and the calculating module is used for calculating the over-Hang value of the lithium battery to be detected according to the negative electrode identification position and the positive electrode identification position.
7. The image projection-based lithium ion battery winding OverHang detection system of claim 6, wherein the construction module is specifically configured to:
the construction module is used for calculating the one-dimensional discrete array A1 according to the following formula:
；
wherein r is i For the number of rows of the bottom-most pixels of the ith column in the active area,for the number of rows of the top-most pixels of the ith column in the effective area, gray is the gray value of the pixels in the effective area, and n is the number of the pixels in the ith column in the effective area.
8. The image projection-based lithium battery winding OverHang detection system of claim 6, wherein the determination module is specifically configured to:
the saidThe determining module is used for taking the index value of the one-dimensional discrete array A1 as an x-axis coordinate value, taking the element value of the one-dimensional discrete array A1 as a y-axis coordinate value, and performing polynomial curve fitting based on a least square method to obtain a continuous function；
The determining module is used for calculating the continuous functionIs>And second derivative->；
The determining module is used for determining the second derivativeThe points of 0 are combined into a one-dimensional discrete array A2, wherein the one-dimensional discrete array A2 represents a continuous function +.>The junctions of the concave functions and the convex functions;
the determining module is used for substituting the one-dimensional discrete array A2 into the first derivative in turnCalculating a corresponding first derivative value, and obtaining a one-dimensional discrete array A3 according to the first derivative value, wherein the one-dimensional discrete array A3 is a gradient value of gray level change corresponding to all suspected edges;
the determining module is configured to compare the one-dimensional discrete array A3 with a preset judgment threshold, extract a point in the one-dimensional discrete array A3 where an absolute value is greater than the judgment threshold, and obtain a one-dimensional discrete array A4, where the one-dimensional discrete array A4 is a suspected edge that conforms to a set gradient value.
9. The image projection-based lithium battery winding OverHang detection system of claim 6, wherein the determination module is specifically configured to:
the determining module is used for taking the maximum value in the one-dimensional discrete array A4 as the edge position of the negative pole piece;
the determining module is used for taking the minimum value in the one-dimensional discrete array A4 as the edge position of the diaphragm.
10. The image projection-based lithium battery winding OverHang detection system of claim 6, wherein the computing module is specifically configured to:
the calculation module is used for calculating a first distance d1 of the negative pole piece relative to the negative pole identification position;
the calculation module is used for calculating a first distance d2 of the positive pole piece relative to the positive pole identification position;
the calculation module is used for calculating the OverHang value of the lithium battery to be detected according to the first distance d1 and the first distance d2; wherein,
the calculation module is used for calculating the over Hang value of the lithium battery to be detected according to the following formula:
OverHang=d2×（P1）-d1×（P2）；
wherein, overHang is the OverHang value of the lithium battery to be detected, P1 is the resolution of the positive camera, and P2 is the resolution of the negative camera.
CN202410167273.9A 2024-02-06 2024-02-06 Lithium battery winding OverHang detection method and system based on image projection Active CN117704968B (en)

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